Tapeworm eggs found in fossilized poop

All the same, you've got to take your hats off to the team at Brazil's Federal University of Rio Grande, for their investigation into ancient tapeworms.

The team's discovered a cluster of tapeworm eggs in 270-million-year-old fossilized shark feces from southern Brazil - 140 million years older than ever found before.

"This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was previously known and occurred at least 270-300 million years ago," the authors write.

The 93 fossilized eggs were found in a cluster very similar to those laid by modern tapeworms. The eggs are around 150 microns long, of which most are un-hatched. One, though, contains what appears to be a developing larva, complete with the hooklets that it would have later used to attach to a host's intestines.

It seems, though, that the remains of such parasites in vertebrates from this era are rare. Of 500 samples found at the same site, only one contained tapeworm eggs. The researchers suggest that the area was once a freshwater pond, where many fish were trapped during a dry spell.

The team says the discovery helps establish a timeline for the evolution of the present-day parasitic tapeworms found in foods like pork, fish and beef.